Advent of Code 2019 - Day 1The Tyranny of the Rocket Equation

| Problem statement | Source code | Tags: Brute force

Part 1

Not much to say about this. Division rounds down by default in C++.

int fuel = mass / 3 - 2;
total += fuel;

Part 2

I bet there's a way to mathematically calculate the limit, but this at most takes $\log_3(w)$ iterations per module, so it's efficient enough.

while (fuel > 0) {
    total += fuel;
    fuel = fuel / 3 - 2;
}